Renowned physicist Stephen Hawking is urging space exploration to save humanity, as the earth is close to expiration.

“Earth is under threat from so many areas that it is difficult for me to be positive,” Hawking says in a recent speech. “We are running out of space, and the only place we can go to are other worlds. It is time to explore other solar systems. Spreading out may be the only thing that saves us from ourselves. I am convinced that humans need to leave Earth.”

This isn’t the first time the physicist has made such claims.

In Expedition New Earth, a BBC documentary, Hawking explores what he believes is necessary to preserve humanity.

“Professor Stephen Hawking thinks the human species will have to populate a new planet within 100 years if it is to survive,” the BBC said. “With climate change, overdue asteroid strikes, epidemics and population growth, our own planet is increasingly precarious.”